(1) Field of the Invention
The present invention relates to a sensor system, and a method for operating such a system, which comprises a sensor apparatus for gathering information, converting the information to digital data and communicating such data via an RF encoded signal to a remote reader system. More specifically, this invention relates to a system for remotely reading the current state of one or more sensor apparatus in a reader field of view whereby the reader transmits an RF signal that is received, modulated and re-radiated by each and every sensor apparatus in the reader field of view. The sensor-module, re-radiated RF signals contain discriminating information and digital data frame. The reader, which will nearly simultaneously receive RF signals from every sensor apparatus in the reader's field of view, can use the discriminating information to identify each specific sensor apparatus so that each digital data frame can be addressed according to the specific sensor apparatus transmitting the data frame.
(2) Description of the Prior Art
New battle-space scenarios (the Expeditionary Sensor Grid, for example) include deploying large numbers of unattended sensors that monitor certain aspects of the environment. The sensors must have low power consumption in order to function unattended for long periods. Further, the sensors should be capable of covert operation. That is, the sensors should not be detectable as a result of reflected or self-generated electromagnetic emissions, even in the visible spectrum. However, in order to be useful, the information gathered by the sensors must find its way to regional data-fusion centers for analysis and evaluation. What is needed, therefore, is a covert and versatile sensor system that can be used in a wide range of physical environments.